Dynamic inferred coupling estimation

Abstract

Systems, methods and apparatus for providing a wireless charging device are disclosed. A method for operating the wireless charging device includes transmitting a first pulse through each of a plurality of charging circuits, determining peak voltage at nodes in the plurality of charging circuits, each node coupling a transmitting coil to a capacitor in one charging circuit in the plurality of charging circuits, the peak voltage at each node being responsive to the first pulse and indicative of a coupling coefficient with a receiving coil in a chargeable device, determining that a minimum peak voltage responsive to the first pulse is associated with a first charging circuit in the plurality of charging circuits, and providing a first charging current to the first charging circuit.

What is claimed is: 
     
       1. A method for operating a wireless charging device, comprising:
 transmitting a first pulse through a first power transmitting coil that is coupled to a first capacitor at a first node in a first charging circuit; 
 determining a first peak voltage, wherein the first peak voltage occurs at the first node in response to the first pulse and is indicative of a coupling coefficient between the first power transmitting coil and a receiving coil in a chargeable device; 
 transmitting the first pulse through a second power transmitting coil that is coupled to a second capacitor at a second node in a second charging circuit; 
 determining a second peak voltage, wherein the second peak voltage occurs at the second node in response to the first pulse and is indicative of a coupling coefficient between the second power transmitting coil and the receiving coil in the chargeable device; 
 determining that amplitude of the first peak voltage is lower than amplitude of the second peak voltage; and 
 providing a first charging current to the first charging circuit. 
 
     
     
       2. The method of  claim 1 , wherein the first peak voltage is representative of a leakage inductance of the first charging circuit. 
     
     
       3. The method of  claim 1 , wherein the first power transmitting coil and the second power transmitting coil are deployed adjacent to a surface of the charging device. 
     
     
       4. The method of  claim 1 , further comprising:
 transmitting the first pulse through a third power transmitting coil that is coupled to a third capacitor at a third node in a third charging circuit; 
 determining a third peak voltage, wherein the third peak voltage occurs at the third node in response to the first pulse and is indicative of a coupling coefficient between the third power transmitting coil and the receiving coil in the chargeable device; and 
 providing the first charging current to the first charging circuit when the first peak voltage is lower than the amplitude of the second peak voltage and lower than the amplitude of the third peak voltage. 
 
     
     
       5. The method of  claim 4 , further comprising:
 detecting that voltage at the node in the first charging circuit exceeds a threshold voltage while providing the first charging current to the first charging circuit; 
 transmitting a second pulse through each of the second charging circuit and the third charging circuit; 
 determining that a minimum peak voltage responsive to the second pulse is associated with the second charging circuit; and 
 providing a second charging current to the second charging circuit. 
 
     
     
       6. The method of  claim 5 , further comprising:
 discontinuing the first charging current when providing the second charging current to the second charging circuit. 
 
     
     
       7. The method of  claim 5 , further comprising:
 redirecting at least a portion of the first charging current to the second charging circuit as the second charging current. 
 
     
     
       8. The method of  claim 5 , further comprising:
 redirecting at least a portion of the first charging current to the third charging circuit when providing the second charging current to the second charging circuit. 
 
     
     
       9. A non-transitory processor-readable storage medium having instructions stored thereon which, when executed by at least one processor of a charging circuit, cause the charging circuit to:
 transmit a first pulse through a first power transmitting coil that is coupled to a first capacitor at a first node in a first charging circuit; 
 determine a first peak voltage, wherein the first peak voltage occurs at the first node in response to the first pulse and is indicative of a coupling coefficient between the first power transmitting coil and a receiving coil in a chargeable device; 
 transmit the first pulse through a second power transmitting coil that is coupled to a second capacitor at a second node in a second charging circuit; 
 determine a second peak voltage, wherein the second peak voltage occurs at the second node in response to the first pulse and is indicative of a coupling coefficient between the second power transmitting coil and the receiving coil in the chargeable device; 
 determine that amplitude of the first peak voltage is lower than amplitude of the second peak voltage; and 
 provide a first charging current to the first charging circuit. 
 
     
     
       10. The processor-readable storage medium of  claim 9 , wherein the first peak voltage is representative of a leakage inductance of the first charging circuit. 
     
     
       11. The processor-readable storage medium of  claim 9 , wherein the first power transmitting coil and the second power transmitting coil are deployed adjacent to a surface of the charging device. 
     
     
       12. The processor-readable storage medium of  claim 9 , wherein the instructions cause the charging circuit to:
 transmit the first pulse through a third power transmitting coil that is coupled to a third capacitor at a third node in a third charging circuit; 
 determine a third peak voltage, wherein the third peak voltage occurs at the third node in response to the first pulse and is indicative of a coupling coefficient between the third power transmitting coil and the receiving coil in the chargeable device; and 
 provide the first charging current to the first charging circuit when the first peak voltage is lower than the amplitude of the second peak voltage and lower than the amplitude of the third peak voltage. 
 
     
     
       13. The processor-readable storage medium of  claim 12 , wherein the instructions cause the charging circuit to:
 detect that voltage at the node in the first charging circuit exceeds a threshold voltage while providing the first charging current to the first charging circuit; 
 transmit a second pulse through each of the second charging circuit and the third charging circuit; 
 determine that a minimum peak voltage responsive to the second pulse is associated with the second charging circuit; and 
 provide a second charging current to the second charging circuit. 
 
     
     
       14. The processor-readable storage medium of  claim 13 , wherein the instructions cause the charging circuit to:
 discontinue the first charging current when providing the second charging current to the second charging circuit. 
 
     
     
       15. The processor-readable storage medium of  claim 13 , wherein the instructions cause the charging circuit to:
 redirect at least a portion of the first charging current to the second charging circuit as the second charging current. 
 
     
     
       16. The processor-readable storage medium of  claim 13 , wherein the instructions cause the charging circuit to:
 redirect at least a portion of the first charging current to the third charging circuit when providing the second charging current to the second charging circuit.